De Rosa Salvatore, Polimeni Alberto, De Velli Giovanni, Conte Micaela, Sorrentino Sabato, Spaccarotella Carmen, Mongiardo Annalisa, Sabatino Jolanda, Contarini Marco, Indolfi Ciro
Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, 88100 Catanzaro, Italy.
Presidio Ospedaliero Umberto I, 96100 Siracusa, Italy.
J Clin Med. 2019 Jul 31;8(8):1143. doi: 10.3390/jcm8081143.
The assessment of the left main coronary artery (LMCA) by coronary angiography has several limitations. The fractional flow reserve (FFR) is useful for the functional evaluation of LMCA stenoses. The instantaneous wave-free ratio (iFR), a resting index, was developed to simplify functional coronary assessment. However, its performance for LMCA stenoses has yet to be explored. The iFR was measured at rest, and the FFR was measured under maximal hyperemia. We calculated that a sample size of 90 lesions would have provided 90% power at a 5% significance level to detect an Area Under the Curve (AUC) < 0.7 for the iFR to identify FFR-positive stenoses. A total of 91 measurements were performed on angiographically intermediate LMCA stenoses at three centers. The comparison between the iFR and the FFR showed a significant correlation (r = 0.67, < 0.001). At receiver operating characteristic (ROC) analysis, the iFR revealed a good diagnostic performance when compared to the FFR (AUC = 0.84; p < 0.001). A classification agreement between the iFR and the FFR was recorded in 81% of cases. The left ventricular ejection fraction (LVEF) was an independent predictor of the discrepancy between the FFR and iFR values (p = 0.040). The present study is the first demonstrating that the assessment of LMCA stenoses with the instantaneous wave-free ratio is a reliable adenosine-free alternative to classic fractional flow reserve. If confirmed in larger populations, these findings could be of relevance for real world daily practice.
冠状动脉造影对左主干冠状动脉（LMCA）的评估存在若干局限性。血流储备分数（FFR）对LMCA狭窄的功能评估很有用。瞬时无波比值（iFR）是一种静息指标，旨在简化冠状动脉功能评估。然而，其对LMCA狭窄的性能尚未得到探索。iFR在静息状态下测量，FFR在最大充血状态下测量。我们计算得出，90个病变的样本量在5%的显著性水平下将提供90%的检验效能，以检测iFR识别FFR阳性狭窄的曲线下面积（AUC）<0.7。在三个中心对血管造影显示为中度的LMCA狭窄进行了总共91次测量。iFR与FFR之间的比较显示出显著相关性（r = 0.67，<0.001）。在受试者工作特征（ROC）分析中，与FFR相比，iFR显示出良好的诊断性能（AUC = 0.84；p < 0.001）。81%的病例记录了iFR与FFR之间的分类一致性。左心室射血分数（LVEF）是FFR与iFR值差异的独立预测因素（p = 0.040）。本研究首次证明，用瞬时无波比值评估LMCA狭窄是一种可靠的无需腺苷的经典血流储备分数替代方法。如果在更大的人群中得到证实，这些发现可能与现实世界的日常实践相关。
